Burglar-alarm.



R. MILLEN.

BURGLAR ALARM. APPLICATION ,mn APR. 21. 1915.

Patented J 11116 20, 1916.

RUDOLPH MILLEN, OF BIRDVILLE, PENNSYLVANIA.

BURGLAR-ALARM.

Specification of Letters Patent.

Patented June 20, 1916.

Application filed April 27, 1915. Serial No. 24,320.

To all whom it may concern:

Be it known that I, RUDOLPH MILLEN, a citizen of the UnitedStates of America, residing at Birdville, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Burglar-Alarms, of which the following is a specification.

This invention relates to certain novel and useful improvements in burglar alarm apparatus and has particular application to apparatus of the class described for use in connection with door locks.

In carrying out the present invention, it is my purpose to provide burglar alarm apparatus which may be readily and quickly applied to a door look without changing the structure of the lock and whereby a signal will be given in the event of anyone tampering with the look.

It is also my purpose to provide apparatus of the type set forth which will embrace the desired features of simplicity, efiiciency and durability, which may be manufactured and marketed at small cost and wherein the component parts will be so arranged and correlated as to reduce the possibility of derangement to a minimum.

With the above and other objects in View, the invention consists in the construction, combination and arrangement of parts hereinafter set forth in and falling within the scope of the claims.

In the accompanying drawing; Figure 1 is a view in front elevation of a door lock equipped with burglar alarm apparatus constructed in accordance with the present invention, the parts being shown in section. Fig. 2 is a view taken at right angles to Fig. 1.

Referring now to the drawing in detail, 1 designates a door lock of appropriate construction, while 2 indicates the key disposed within the keyhole of the lock and capable of movement to project and retract the locking bolt.

My improved burglar alarm apparatus comprises a split clamp collar 3 preferably formed of spring metal and having the ends thereof outturned and formed with alining threaded openings to receive a clamping screw 1. This collar 3 is adapted to surround the shank of the key 2 as shown in the drawing and when applied to the key the screw 4 is tightened to securely clamp the collar upon the key. Formed in the upper portion of theeollar 3 is a threaded opening 5. 6 designates a sheet of metal stamped to form crossed arms intersecting each other at right angles and having the extremities thereof upturned as at 7 and the central portion formed with a threaded opening 8 adapted to aline with the opening 5 to receive a securing screw 9 whereby the sheet of metal may be secured to the clamping collar 3 and disposed in a horizontal position. 10 indicates a contact arm having one end portion bent upon itself to form a hook 11 and the hook 11 is adapted to surround the knob spindle of the look, as illustrated in the drawing. The outer end of the bill of the hook 11 is formed with a threaded opening and alining with such opening is a second opening formed in the main body portion of the arm and threaded through these openings is a clamping screw 12 whereby the bill of the hook may be drawn around the knob spindle tightly to hold the contact arm to the knob spindle. The collar 3 and the hook 11 on the contact arm 10 are equipped with binding screws 13 and 14 respectively, and, in practice, the terminals of an electric circuit 15 are connected to the binding screws 13 and 14 respectively and this circuit includes a suitable source of energy as a battery 16, a bell 17 and a switch 18 whereby the circuit may be opened and closed.

In practice, after the key 2 has been turned in the lock to eject the locking bolt, the collar 3 carrying the sheet of metal 6 is secured to the key and the sheet of metal disposed in a horizontal position, while the hook 11 is secured to the knob spindle as just described, and the lower end of the contact arm 10 is disposed at a point approximately centrally of the metal 6. The switch 18 is now closed and should anyone, attempting to force the lock, turn the knob spindle, the lower end of the contact arm 10 will be brought into engagement with the plate 6, thereby closing the circuit and sounding the alarm.

I claim: 7

1. A circuit closer for attachment to the inserted key of a door lock and the knob spindle comprising a clamping collar for attachment to said key and to which one terminal of an alarm circuit is adapted to be connected, a plate carried by said collar, a contact arm for attachment to said spindle and to which the other terminal ofan alarm circuit is adapted to be connected, and means for securing said contact arm to said spindle; said contact arm being normally spaced apart from said plate but movable into engagement therewith by the turning of said spindle.

2. A circuit closer for attachment to the inserted key of a door lock and the knob spindle comprising a clamping collar for attachment to said key and to which one terminal of an alarm circuit is adapted to be connected, a plate carried by said collar, a contact arm for attachment to said spindle and to which the other terminal of an alarm circuit is adapted to be connected, said contact arm having the spindle end thereof formed to provide a hook adapted to encircle the spindle, and a clamping screw carried by said hook and'adapted to bind the hook portion of the arm tightly to the knob spindle, said contact arm being normally spaced apart from said plate but movable into engagement therewith by the turning of said spindle.

In testimony whereof I afiix my signature in presence of two witnesses.

RUDOLPH MILLEN. Witnesses:

H. STANLEY BURK, D. N. BURTNER.

copies or thin patent may be obtained for five cents each, by addressing the Commissioner of rated, Washington, D. 0." 

